This invention relates to radiant heaters, and, more particularly, to a radiant heater which includes a burner having improved radiation efficiency and reduced emissions.
Radiant heaters generally include a fuel source, such as propane or gasoline, a burner for burning the fuel and creating radiant heat energy, and a reflector for directing the radiant energy from the burner to the area which is to be heated. It is desirable that the fuel be burned as completely as possible to maximize the efficiency of the heater and to reduce the emission of unburned hydrocarbons.
The invention provides a porous burner with two different wire cloth meshes. The mesh of the outer portion of the burner away from the reflector is finer than the mesh of the inner portion of the burner. The burner is mounted on a burner tube which supplies fuel and combustion air to the burner, and a cylindrical port screen is mounted on the end of the burner tube inside the burner. The finer mesh of the outer half of the burner forces a higher percentage of the burning air/fuel mixture to flow through the inner half of the burner. The air/fuel mixture is thereby retained within the burner for a longer time, and emissions are decreased. The inner half of the burner, which is closer to the reflector, is heated to a higher temperature than the bottom half, and the radiation efficiency of the heater is increased. The cylindrical port screen slows the flow rate of the air/fuel mixture, diffuses the mixture, and decreases noise and emissions.